EFFECTS OF AMPHIPHILIC COMPOUNDS ON METABOLIC AND BIOLOGICAL-ACTIVITIES OF SALMONELLA-TYPHIMURIUM

The effect of two quaternary ammonium salts, (1-methyldodecyl)trimethy lammonium bromide (ATDBr) and tetramethylammonium bromide (TMABr), as well as that of two amine oxides, (1-methyldodecyl) dimethylamine oxid (ATDNO) and trimethylamine oxid (TMANO), on both metabolic and biolog ical activities of a S. typhimurium strain isolated from nosocomial in fection were studied. The compounds with long alkyl chain in the molec ule (ATDBr, ATDNO) affected the growth, synthesis of biomacromolecules (DNA, RNA, proteins) and respiration. The compounds lacking the alkyl chain (TMABr, TMANO) were ineffective with exception of the endogenou s respiration that they inhibited in a less degree in the highest conc entrations tested. The highest inhibition of respiration was evoked by ATDBr and ATDNO in the presence of pyruvate as an exogenous carbon su bstrate. The sub-MICs of quaternary ammonium salts induced a prophage of the lysogenic S. typhimurium strain, amine oxides were ineffective. The tested compounds decreased at one-fourth of the MICs the permeabi lity reaction. The results showed that both physiologic and metabolic processes were inhibited in dependence on the length of the alkyl chai n, however, amine oxides were less effective in biological activities.